/Engine/Source/Runtime/Engine/Classes/Engine/TwitterIntegrationBase.h
Kicks off a tweet, using the platform to show the UI. If this returns false, or you are on a platform that doesn't support the UI, you can use the TwitterRequest method to perform a manual tweet using the Twitter API
true if a UI was displayed for the user to interact with, and a TID_TweetUIComplete will be sent
virtual bool ShowTweetUI ( const [FString](API\Runtime\Core\Containers\FString) & InitialMessage, const [FString](API\Runtime\Core\Containers\FString) & URL, const [FString](API\Runtime\Core\Containers\FString) & Picture )